


The Great Pull-Up Battle

by LittleFandomStories



Series: Little Hiro [2]
Category: Big Hero 6 (2014)
Genre: Age Play, Infantilism, Non-Sexual Age Play, little!Hiro
Language: English
Status: Completed
Published: 2015-04-15
Updated: 2015-04-15
Packaged: 2018-03-23 02:26:18
Rating: Not Rated
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,576
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/3750988
Author URL: https://archiveofourown.org/users/LittleFandomStories/pseuds/LittleFandomStories
Summary: <blockquote class="userstuff">
              <p>Hiro Hyper-Focuses and potty breaks aren't on the agenda. Tadashi Is not happy about it and tries to help. Ever wonder why Hiro is in a pull-up all the time?</p>
            </blockquote>





	The Great Pull-Up Battle

**Author's Note:**

> Chronologically this takes place before First Day Blues.

Tadashi heard him coming, his little brother who had all the subtly of a charging rhino in a china shop, and contemplated locking the door to the bathroom. It was a normal thing people did, Aunt Cass locked it all the time because Hiro liked to barge in, and maybe a bit of waiting would teach him not to hold it for so long. Maybe an accident even would be enough to break the habit, Tadashi considered as his hand hovered by the door’s lock.

With a sigh Tadashi twisted the handle and flung the door open just in time for Hiro to dash in. Tadashi shook his head as Hiro bounced from foot to foot, fighting with the button to his shorts. The older Hamada brother waited until he was certain Hiro wasn’t going to pee his pants two feet from the toilet before he turned back to the finishing his post-shower grooming.

“You know,” Tadashi started, “You wouldn’t have to rush if you remembered to take potty breaks.”

Hiro shrugged his shoulders, “Yeah, well I don’t have time for that. More important things to do.”

“Your work isn’t going anywhere,” Tadashi flicked his toothbrush at his brother, “It’s your body you have to take care of.”

Hiro rolled his eyes as he pulled his pants up and headed for the door, it was the same speech Tadashi always gave him. Take care of your body, keep my tools out of your mouth, and go to the bathroom. Nag, nag, nag, nag, nag.

“Oh no you don’t.” Tadashi snagged Hiro by the collar, “flush.”

“You’re going to go aren’t you?” Hiro pulled the hand off his collar, “Saving water and all that.”

“Then wash your hands.”

Hiro eyed the sink, making sure it was Aunt Cass’ brand of soap and not Tadashi’s. He had a type of soap that made Hiro’s fingers taste disgusting and he hated it. With a huff, because what was life without the theatrics, Hiro washed and dried his hands as Tadashi got dressed.

“Happy now?” Hiro asked as he cycled his fingers through his mouth to make sure he had used the right soap.

“That depends.” Tadashi grabbed Hiro’s head and looked at it, turning it this way and that.

“Stop that!” Hiro whined, trying to pull away.

First the ‘take care of your body speech’ now this? It really only means one thing and Hiro really, really wanted to be wrong.

“That’s what I thought.” Tadashi nodded to himself, having found what he was looking for, “You haven’t been sleeping again have you?”

“’Dashi,” Hiro whined, squirming to get away, “I have stuff to do. I’m this close to finishing my new bot!”

“And you’ll still be that close after you take a nap.” Tadashi hauled the squirming boy into his arms and made way towards the stairs, “It’ll be fun.”

“Naps are never fun ‘Dashi.” Hiro whined, “Building bots is fun.”

Tadashi rolled his eyes, keeping a firm grip in the struggling Hiro as he climbed the stairs. Nothing quite sent Hiro into being little like being tired, and Tadashi didn’t like leaving him in his workshop like that. Too many dangerous tools and too little sharp focus. Last time that had happened, Tadashi found Hiro making robotic building blocks that shook the higher off the ground they got. It would have been fine and fun except they each weighed about ten pounds and had let bruises all over Hiro’s arms and legs from playing with them.

“This one will be. I’ll even read you a story.”

“About robots?” Hiro perked up.

“No, not this time.” Hiro never napped well after books with robots, he kept trying to conceptualize the characters so he could recreate them, “How about the one with the pig and the pancakes?

“I guess.”

It was part of Tadashi’s master plan, make Hiro sleep and get him thinking about food. It would ensure he ate later and not just a bag of gummy bears.

“Alright then.”

The fact that Hiro didn’t struggle half as much as he usually did as Tadashi helped him change out of work clothes and into nap clothes, which was really just one of Tadashi’s old shirts, affirmed to Tadashi that he needed the nap. Getting settled, which meant he was sitting up uncomfortably while Hiro was pressed into his side and fingers occupying his mouth, Tadashi pulled the book form the night stand.

“If you give a pig a pancake…”

* * *

 

“Tadashi, put me down!”

“Not going to happen.”

Aunt Cass sighed as she heard the boys fighting their way up the stairs. This was becoming an everyday thing with those two. It was almost enough to drive her to stress eating.

Her eyebrow raised itself as Tadashi set Hiro down in front of her with his ‘worried and upset’ look on his face.

“Tell her Hiro.”

“There’s nothing wrong.” Hiro insisted.

“Which means something is wrong.” She interjected, leaning on the counter, “So tell me.”

“He said ‘ow’ when he was peeing this morning.” Tadashi finally stated when Hiro crossed his arms defiantly, “Not to mention it smelled bad.”

“So you two were in the bathroom together again.” Her smile was one of amusement, “Thought you two would have outgrown that.”

In reality she knew they never would, just like how they would never outgrow sticking things in their mouths. They had been sharing a bathroom for so long and Tadashi was so concerned about his brother that personal privacy was non-existent between them.

But where was the fun in life if she didn’t tease them?

Tadashi huffed in embarrassment and Hiro shrugged it off, scouting for an exit. Time to do her thing.

“Anyway. Hiro, come here for a second.” She stepped around the counter and crouched down.

“Yes?”

“Does it hurt when you pee?”

Hiro blinked, “A little.”

“And it smells funny?”

Hiro looked at Tadashi, “Tadashi says so.”

“He’s been soldering and printing all morning. It kind of fills up your nose.” Tadashi chimed in.

“One last thing okay?”

When Hiro nodded, Aunt Cass took her hand and pressed it gently on the lower part of his stomach. Hiro yelped, jumping away from her. With a sigh, Cass rose to her feet and untied her apron.

“Alright kids, we have to go to the doctors. Let’s go.”

Tadashi frowned, putting a hand on Hiro’s shoulder, “What’s wrong?”

“It sounds like Hiro’s got a UTI.” She grabbed her keys and purse, double checking she had everything, “And we need to go to the doctors to get it cleared up.”

“How did I get one?”

“Probably from holding it so much Hiro.”

Hiro paled at the answer and Tadashi frowned as he guided Hiro into following their Aunt. This was the kind of thing he tried to avoid having happen to Hiro.

 

* * *

 

Hiro glared at the object on his brother’s hands, not quite believing what he was seeing. There was no way his brother was expecting him to use that.

“No.”

Tadashi leveled a look at his brother, “Hiro, if you keep this up you’re going to get sick. Again. And I know you don’t want that to happen.”

He wasn’t wrong, Hiro had hated the weeks with the UTI. It hurt, he felt like he always had to pee, and he occasionally leaked in his pants.

“That doesn’t mean I’m going to use that.”

The object in question was a red training potty that Hiro could see Tadashi had taken the time to carefully write his name on it. Part of him, the part that like to cuddle and be read stories, was curious about it. The other part, however, was angry at the very idea of having to sit on that thing.

“Then don’t use it, use the big potty.” Tadashi set it down, “but If I have to come find you and make you go, it’s gonna be on this.”

Taking Hiro’s silence as a cue, Tadashi pulled out the other thing he had bought. Hiro’s eyes tracked the sticker book like it was worth a million dollars.

“Robot stickers?”

“Robot stickers. For when you willingly go use the potty.”

He could see Hiro doing the math, eyeing both the potty and the stickers, and knew his plan was going to work for now. Hiro was a sucker for stickers and he wasn’t going to drag the boy through the house each time he wanted Hiro to use the toilet.

All of that in mind, he still blinked when Hiro dropped his pants and sat on the small potty, red face hidden by his hair. Tadashi took that moment to glance around his brother’s workshop, inspecting the new inventions littering the table and pocketing one tool that he knew was his.

“’Dashi, sticker.”

Hiro’s face was red as he pulled his pants up and stared his brother down. Tadashi took the time to show his brother how to clean it first, so Hiro wouldn’t have an excuse not to do it, before handing one of the stickers to him. After a moment of contemplation, because where Hiro put the sticker was extremely important to him, he carefully put it on the little potty.

“Good job Hiro.”

Hiro squirmed as Tadashi planted a kiss on the top of his head. Why did he have to do embarrassing things like that?

“Come on, Aunt Cass is making wings tonight.”

That was all it took to get Hiro moving, shutting his stuff down and dragging Tadashi towards the house. Nobody made wings better than Aunt Cass.

 

* * *

 

Tadashi knew his plan wasn’t going to work forever, but he had hoped it would have been more than a week. Sure Hiro used the potty on occasions, sometimes he even managed to make it up to the big one without having to run, but he was still waiting till the last minute.

“Hiro, that’s the third pair today.”

The problem was he had developed a leaking problem while in his workshop. He’d get so focused on whatever he was working on that when his bladder hit the full point, he’d unconsciously let enough out to take the edge off so he could focus. Of course, most of the time he’d notice and stop and go to the bathroom but sometimes it wouldn’t be enough to knock him out of focus.

Today was one of those days and Hiro had the decency to look embarrassed as he sat on the potty.

“Well, I’m stumped.” Tadashi sighed as he pulled a chair across from Hiro, “You’ve gone through all your underwear Hiro. All of ‘em in the wash.”

“I’m sorry.” Hiro mumbled around his fingers, “I don’t mean to do it.”

Tadashi couldn’t argue that point, it was like blaming a safety valve for going off on a water heater.

“We’ve got to do something Hiro.” He kept his voice calm, “This can’t keep happening.”

“I know.”

“Maybe we should close up the workshop for a while.” At the mutinous look on Hiro’s face, he continued.

“It only happens when you’re working down here Hiro. Maybe if you take a break from all these big projects for a while we’ll figure something out.”

“No!”

Hiro was on his feet, his face scrunched up in anger and hands balled up in fists. Tadashi groaned, of course he’d throw a fit.

“Hiro…”

“No! We’re not closing my workshop!” Hiro’s foot stomped and he shoved Tadashi’s chair towards the exit of the workshop, “Get out!”

Tadashi sighed and scooped him up, weathering the storm of yelling and flailing as he shut everything down. It took a bit of work to put in the lockdown codes without Hiro seeing them but he did it. Ten minutes later, because Hiro had wiggled down at one point and started hacking his way through the lockdown before Tadashi snatched him back up, he was dozing lightly on his bed with Hiro curled up in sight on his own bed.

“Everything okay with you two?”

He blinked awake as Aunt Cass set the basket with Hiro’s clean clothes down. He knew he had forgotten about something.

“Yeah, mostly.”

He sat up, intending to get up and help her, but she pushed him back down.

“Get some sleep Tadashi. I can handle putting away Hiro’s underwear.” She pulled open the appropriate drawer and started putting them away, “I swear he hasn’t gone through this many pairs since he was four. He had accidents left and right back then.”

Her chatter, because Tadashi recognized it for what it was, sparked an idea in his brain as he dozed off again. Maybe this idea would stick.

 

 

With Hiro stuck sulking around the house and using their shared workbench in their room, Tadashi had a bit more free time to himself than he usually did. Well, after he snuck into the workshop to bring Hiro’s little potty up because he didn’t quite trust the moody boy to get up and go use the big one every time.

Hiro had only fallen in the toilet once when he was younger.

The upside was, aside from being able to go to the lab and have a social life now that his brother wasn’t giving himself UTIs or wetting through four pairs of underwear a day, and also slowly implement his new plan.

“Hiro, I have a deal for you.”

Hiro blinked from where he was playing with a toy spaceship on his bed, “What?”

“I’ll unlock your workshop under one condition.”

That got his immediate attention, “What is it?”

Hiro was wary, which wasn’t good for the plan. A wary Hiro meant an argumentative Hiro. But he was going to give it his best shot anyway and tossed Hiro the package he picked up on his way back from the lab today.

“No. Not worth it.” The response was immediate.

“Hiro…”

“I’m not a baby and I don’t need diapers.” Hiro snarled, tossing the package back at him with more force than necessary.

“Then No workshop then.”

An argument was what Hiro wanted because it would let him alter the agreement to suit him.

“That is completely unfair ‘Dashi!” Hiro flopped back down.

“So is Aunt Cass having to wash your underwear on a nightly basis.” Tadashi kept his voice soft.

The room was silent for a few minutes as Hiro grumbled and Tadashi read. If there was one thing he could count on, it was his ability to be more patient than Hiro.

The minutes ticked by, Tadashi turned the page and scribbled some notes, and Hiro rolled around.

“I’m not a baby.”

“Nobody says you are.”

“I don’t need diapers.”

“Those aren’t diapers. You should read more carefully kid.”

Tadashi was aware of Hiro getting up and inspecting the package but made no move otherwise. Better to let him do things on his own so he can’t accuse Tadashi of pressuring him.

“I put one of these on and you open the workshop back up?” Hiro spoke slowly, contemplating the options.

“Yep.”

There was the sound of tearing plastic followed by the rustle of clothes being shifted around. Tadashi turned another page, constantly reminding himself to let Hiro do it on his own.

“There. Now unlock the workshop.”

Tadashi set the book down and finally faced his brother. Nothing was overtly visible but he could see the top of the pull-up poking out where Hiro hadn’t pulled his shirt out. With a nod to himself, Tadashi scribbled a math equation on a piece of paper and handed it to Hiro.

“Solve it and it’s the code to lift the lockdown.”

Hiro snatched it and scrambled for his desk, his pencil scratching away for a few minutes before he took off down the stairs. Tadashi smiled to himself, it was nice to see Hiro energetic after a few days of moping around. He’d give him a few hours before pulling him back out to sleep tonight.

A few hours later Tadashi, with a clean pull-up and Hiro’s potty in hand, made his way down to the workshop, glad it was poetry night so Aunt Cass didn’t have to see him carrying everything back down.

“Hiro.” He groaned the moment he walked in, spotting the dark spot on his brother’s pants in an instant.

“What?” Hiro looked up from where he was engrossed in some programming error.

“Just come here.”

When Hiro was close enough, Tadashi pulled his pants down in a motion honed from years of pantsing his brother. The pull-up was, of course, soaked.

“Oh.”

“Yeah, oh.” Tadashi fumbled for a moment with tearing the sides before getting it right, “You still have to use the potty with these Hiro.”

“My potty wasn’t down here.” Came the snarky reply.

“And you could have run to the big one.”

“Was busy.”

Tadashi ran a hand through his hair, “I noticed. But your potty is down here now so no excuse alright?”

“Mhm.”

“And Hiro, they aren’t diapers. They hold enough that you notice but don’t make a mess.”

“Okay ‘Dashi.”

With that Hiro was back in his chair, typing away. Tadashi sat there for a while, making use of the old couch Hiro crashed on when he was pulling long stints in the workshop, until he saw Hiro stiffen almost half an hour later and dash to the potty.

“Good job Hiro.”

Of course that got him a sticker too.

 

* * *

 

It was quiet in the house and, Cass would admit, that it was a little weird. Hiro was down working in his workshop and she had pushed Tadashi out the door yesterday to go to his lab and work with his friends. He had been spending so much time at home dealing with Hiro he hadn’t seen them in a while. So it was just her, Mochi, and a monster movie.

She hadn’t had a night like this in a long time.

It was only after the movie, and the sequel was over that she realized Hiro hadn’t come rushing through the house once in two days. A glance at the clock revealed that it was midnight, not that that meant anything because everyone kept odd hours in her household, and decided that she was going to go see Hiro. Maybe take him a cupcake.

When she opened the door to the workshop, she immediately wrinkled her nose. The smell of urine filled the air and a quick glance revealed it wasn’t from the small boy’s potty chair. As she crossed the room to where Hiro was steadfastly wiring a gauntlet with what suspiciously looked like rockets attached to it, she couldn’t help but notice the dark spots on the concrete. Some were big puddles and others were vague lines where Hiro had clearly been moving at the same time.

“Hiro.” She said slowly, as to not startle him.

“Aunt Cass!” He spun around, rubbing one eye, “What time is it? What day is it?”

“Midnight and Saturday.” She answered, used to such questions.

“Wow. Look what I made!” He held up the gauntlet, chattering away about what it did and how cool it was.

“Hiro,” she cut him off, “when was the last time you changed?”

Hiro blinked at her and shrugged, “Friday?”

“Come on, back to the house.”

Hiro sighed as he rose to his feet, stretching his back, then took a step to follow her and winced.

“Aunt Cass?”

“Yes?”

“My legs hurt.”

She sighed and took his hand, “Then let’s get you cleaned up and look at them.”

 

Tadashi hadn’t been expecting the phone call telling him to come home, and definitely hadn’t been expecting to see a red faced Hiro sitting on his potty with Aunt Cass stating him down.

“What did I miss?” He said with a sigh as he set his bag down.

“Well Tadashi, Hiro has diaper rash.” Aunt Cass said, not quite taking her eyes off Hiro.

“How?”

“Tell him Hiro.”

It was quiet as they waited for Hiro to answer. Tadashi got a glass of water and offered it to Aunt Cass, who turned it down.

“I didn’t change.” Hiro finally mumbled, “And I had a lot to drink.”

“Your potty was right there Hiro.”

“Tadashi, no.” She cut him off, “I read him the riot act already. He doesn’t need to hear it twice.”

“Ah.” Tadashi took another drink before running his fingers through his hair, “I don’t know what to do Aunt Cass. I’ve tried everything except for diapers.”

Hiro whined, but didn’t get up. He couldn’t get up until he went and he hadn’t.

“None of those.” Aunt Cass mused, “They won’t do anything to make him use the toilet, which is the problem.”

“Don’t I get a say?” Hiro interjected, “I can use the potty.”

“You can but you don’t.” Tadashi shot back, a bit more forceful than he intended, “That’s your say.”

“Tadashi.” Cass warned, “No need to be mean.”

“Right. Sorry Hiro.” Tadashi’s phone spun in his hand, “I have an Idea.”

“Please share.”

Tadashi pulled up what he had been looking at earlier that week and handed the phone over. Aunt Cass read over it, about pull-ups that went cold when wet to help kids learn when to go.

“That, Tadashi, is a great idea.”

 

“I don’t like these.” Hiro whined as he walked into the bathroom.

“But they work.” Tadashi said as he followed Hiro in, watching as the younger boy sat down.

“They’re cold.”

“That’s the point.”


End file.
